1. Field of the Invention
The present invention relates to a linear motion guide apparatus, and more particularly to a linear motion guide apparatus having a ball retaining device for stably and solidly retaining balls or rollers therein and for preventing the balls or rollers from being disengaged from the linear motion guide apparatus.
2. Description of the Prior Art
Various kinds of typical linear motion guide apparatuses have been developed and comprise a bearing device or a slider slidably attached onto an elongated track rail and movable along the elongated track rail which is normally arranged or disposed or provided on a stationary portion, such as a bed of a machine tool, for guiding a movable member, such as a table along the elongated track rail.
For example, U.S. Pat. No. 5,544,954 to Osawa discloses one of the typical linear motion guide apparatuses and also comprises a bearing device or a slider slidably attached onto and movable along an elongated track rail, a number of endless rolling elements or bearing elements disposed between the slider and the elongated track rail for smoothly guiding the slider to move along the elongated track rail, and one or more ball retainers attached to the slider for engaging with the rolling elements or bearing elements or balls or rollers and for stably attaching the balls or rollers to the slider, and for preventing the balls or rollers from being disengaged from the slider.
For preventing the balls retainers from being disengaged from the slider, the balls retainers each include two end locking parts or curved portions for engaging with the slider and for stably attaching the balls retainers to the slider. However, the curved end portions of the balls retainers have not be solidly secured to the slider and may be easily disengaged from the slider when the balls or rollers are forced or moved against the balls retainers, such that the balls or rollers may have a good chance to be disengaged from the slider.
U.S. Pat. No. 6,520,681 to Ishihara discloses another typical linear motion guide apparatus also comprising one or more endless rolling elements or bearing elements disposed between a slider and an elongated track rail, for smoothly guiding the slider to move along the elongated track rail, and comprising two frames attached to an outer housing, for retaining or attaching the endless rolling elements or bearing elements between the frames and the outer housing, and one or more ball retainers attached to the slider for engaging with the rolling elements or bearing elements or balls or rollers and for stably attaching the balls or rollers to the slider, and for preventing the balls or rollers from being disengaged from the slider.
The balls retainers each also include two bent engaging ends for engaging with the slider and for stably attaching the balls retainers to the slider. However, the bent engaging end portions of the balls retainers also have not be solidly secured to the slider and may also be easily disengaged from the slider when the balls or rollers are forced or moved against the balls retainers, such that the balls or rollers may also have a good chance to be disengaged from the slider.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional linear motion guide apparatuses.